This Phase II application continues development of the Screener for Opioid Abuse Potential (SOAP), a brief, self-administered measure to identify which chronic pain patients being considered for long-term opioid therapy are at risk for medication-related abuse or aberrant behavior. No validated procedure exists for this purpose. Phase I began a rigorous and methodical scale development process. Concept Mapping procedures integrated input from pain and addiction experts and patients to generate and conceptually evaluate items for a SOAP alpha version. Concept Mapping also facilitated creation of an operational definition of abuse/aberrant behavior in chronic pain patients to be used as the criterion in Phase II. An initial empirical feasibility test, using cross sectional methods, resulted in a beta version of the SOAP. Phase II will continue item selection using prospective methods to create a final version with good reliability and predictive validity. The final version will then be cross-validated. ROC analyses will identify cutoff scores with maximal sensitivity and specificity, and different cutoff values will be examined with respect to pre-test probabilities of abuse and aberrant behavior. Substantial Phase III support has been committed by Endo Pharmaceuticals. The resulting measure should be reliable, valid, and easy to use in practice settings.